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US 5,028,850 AGranted
Deflection system with a controlled beam spot
AssigneeRCA Licensing Corporation
InventorsMichael D. Grote, Jeffrey P. Johnson, Dennis J. Bechis
Life of this patent
Estimating the term…
Abstract
A deflection apparatus produces a field gradient that reduces a tendency of a major axis of a beam spot to become elongated at each corner, at each end of a horizontal axis and at each end of a vertical axis of a display screen relative to the beam spot at the center of the display screen. A beam spot stigmator causes the beam spot to be substantially anastigmatic at each of the corners, the end of the horizontal axis and the end of the vertical axis of the display screen.
Claims63
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an eletron beam that forms a beam spot at each of electron beam landing locations on said screen;
- a first horizontal deflection coil for producing a first horizontal deflection field and a first vertical deflection coil for producing a first vertical deflection field in a main deflection region of a beam path of said electron beam that varies in a manner to vary the electron beam landing location of said beam spot such that a major axis of said beam spot tends to become elongated when said beam spot is deflected to a first beam landing location along one of a horizontal axis and a vertical axis of said display screen and to a second beam landing location along a diagonal axis of said display screen relative to when said beam spot is deflected to a third beam landing location;
- means for producing in a first region of said beam path a first nonuniform field containing a time varying field portion not produced by said horizontal and vertical deflection coils, said first nonuniform field producing an electron beam lensing action with respect to a cross section of said electron beam in said first region in a manner that varies in accordance with beam landing location for substantially reducing the tendency of said major axis of said beam spot to become elongated at each of said first and second beam landing locations;
- and
- a beam spot stigmator for producing a time varying, second nonuniform field that varies in accordance with beam landing location in a second region of said beam path that is at a different distance from said display screen than said first region, for producing an electron beam lensing action with respect to a corresponding cross section of said electron beam in said second region in a manner that varies in accordance with beam landing location to reduce a tendency of said beam spot to become astigmatic when said beam spot is at each of said first and second beam landing locations.
2 more elements
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at each of electron beam landing locations on said screen;
- a deflection yoke including horizontal and vertical deflection coils magnetically coupled to a core made of magnetic material for producing corresponding field components of a main deflection field in a main deflection region that causes the beam landing locations to vary upon deflection such that a major axis of said beam spot tends to become elongated when said electron beam is deflected to a first beam landing location along one of a horizontal axis and a vertical axis, and to a second beam landing location along a diagonal axis of said display screen, relative to when said electron beam is deflected to a third beam landing location;
- and
- means for producing a deflection current in a third deflection coil that is magnetically coupled to said core that varies in accordance with beam landing location to vary a field gradient in a path of said electron beam in said main deflection region in a manner that reduces the tendency of said major axis of said beam spot to become elongated at each of said first and second beam landing locations.
1 more element
A deflection apparatus comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at each of electron beam landing locations on said screen;
- a deflection yoke including horizontal and vertical deflection coils, each surrounding a neck portion of said cathode ray tube and magnetically coupled to a core made of a magnetic material, for producing in a main deflection region a deflection field to deflect the electron beam to said beam landing locations, such that a major axis of said beam spot tends to become elongated when said beam spot is deflected to each of a plurality of said beam landing locations relative to when said beam spot is at a first beam landing location, said deflection yoke including a third deflection coil magnetically coupled to said core and having a winding distribution that includes a harmonic Fourier component of a higher order than a fundamental Fourier component for producing in said main deflection region a field gradient of said deflection field;
- and
- means for producing a deflection current in said third deflection coil that varies in accordance with beam landing location to vary said field gradient in a path of said electron beam in said main deflection region in a manner that reduces the tendency of said major axis to become elongated at each of said plurality of said beam landing locations.
1 more element
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a deflection yoke including a core made of magnetic material and a plurality of deflection windings for producing a main deflection field in a main deflection region of a deflection yoke that deflects the electron beam to said landing locations, said plurality of deflection windings including first and second deflection windings responsive to first and second deflection currents and magnetically coupled to said core for producing first and second deflection fields, respectively, that are both either mainly horizontal deflection fields or mainly vertical deflection fields such that first and second winding-current product distributions of said first and second deflection windings, respectively, each contain an odd harmonic Fourier component greater than a second harmonic;
- and
- means for generating said first and second deflection currents having a first ratio therebetween that varies in accordance with beam landing location.
1 more element
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a plurality of deflection windings for producing a main deflection field in a main deflection region of a deflection yoke that deflects the electron beams to said landing locations;
- and
- a first quadrupole arrangement for producing, in a first deflection region closer to said display screen than said main deflection region, a first quadrupole magnetic field that varies in accordance with the beam landing locations.
1 more element
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a plurality of deflection windings including a horizontal deflection winding and a vertical deflection winding to form a deflection yoke for producing a deflection field in a main deflection region of a beam path of said electron beam that varies in a manner to vary the electron beam landing location of said beam spot upon deflection such that, as a result of a geometrical shape of said display screen, a major axis of said beam spot tends to become elongated when said beam spot is at a first beam landing location along a horizontal axis and at a second beam landing location along a diagonal axis of said display screen relative to when said beam spot is at a third beam landing location along said horizontal axis;
- a third winding of said plurality of deflection windings responsive to a deflection current that varies in accordance with the beam landing location for producing in said main deflection region a field gradient of said deflection field that varies in accordance with the variation of the beam landing location in a manner that substantially reduces the tendency of said major axis to become elongated at each of said first and second beam landing locations.
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope, and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a deflection yoke disposed on said cathode ray tube for producing a deflection field in a main deflection region between a beam entrance end and a beam exit region of said yoke that causes the electron beam landing location to vary upon deflection;
- and
- means for producing a field nonuniformity in a beam path in said main deflection field in a vicinity of said electron beam when the beam landing location is at a corner of said display screen of a type that can be produced in at least a substantial portion of said beam path in said main deflection region by a pincushion shaped horizontal deflection field combined only with a pincushion shaped vertical deflection field.
1 more element
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a plurality of deflection windings for producing a main deflection field in a main deflection region of a deflection yoke that varies the electron beam landing location such that, as a result of a geometrical shape of said display screen, a major axis of said beam spot tends to become elongated when said beam spot is deflected to each of a plurality of said beam landing locations relative to when said beam spot is at a first beam landing location;
- and
- a first quadrupole winding of said plurality of deflection windings for producing a first quadrupole field in said main deflection region that causes a cross section of said electron beam in a beam path within said main deflection region to converge in a first direction when said beam spot is deflected to each of said plurality of beam landing locations for reducing the tendency of said major axis to become elongated at each of said plurality of beam landing locations.
1 more element
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a plurality of deflection windings for producing a main deflection field in a main deflection region of a deflection yoke that deflects the electron beam to said plurality of beam landing location such that a major axis of said beam spot tends to become elongated when said beam spot is deflected to each of a plurality of beam landing locations relative to when said beam spot is at a first beam landing location;
- a first quadrupole arrangement for producing in a first region a first quadrupole field that varies in accordance with beam landing location for reducing the tendency of said major axis to become elongated at each of said plurality of beam landing locations;
- and
- a second quadrupole arrangement for producing in a second region located at a different distance from said display screen than said first region, a second quadrupole field that varies in accordance with the beam landing location for reducing a tendency of said beam spot to become astigmatic at each of said plurality of beam landing locations.
2 more elements
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at each of electron beam landing locations on said screen;
- a core made of a magnetic material;
- horizontal and vertical deflection windings that are, each, magnetically coupled to said core for producing a main deflection field in a main deflection region, between a beam entrance end and a beam exit end of said core that varies a beam path within said main deflection field and that varies the beam landing location upon deflection such that a major axis of said beam spot tends to become elongated when said beam spot is at each of a plurality of said beam landing locations relative to when said beam spot is at a first beam landing location;
- means for producing horizontal and vertical deflection currents in said horizontal and vertical deflection windings, respectively;
- a third winding;
- means for producing a third current in said third winding that varies in accordance with beam landing location to produce a field gradient in a first region of said beam path of said electron beam such that each of a first ratio between said third current and said horizontal deflection current and a second ratio between said third current and said vertical deflection current varies in accordance with beam landing location in a manner to reduce the tendency of said beam spot to become elongated at each of said first plurality of beam landing locations;
- and
- a beam spot stigmator including a fourth winding responsive to a fourth current that varies in accordance with beam landing location to produce a field gradient in a second region of said beam path that is at a different distance from said display screen than said first region to reduce a tendency of said beam spot to become astigmatic at each of said first plurality of beam landing locations.
5 more elements
A deflection apparatus, comprising:
- a cathode ray tube including an evacuated glass envelope, a display screen disposed at one end of said envelope and an electron gun assembly disposed at a second end of said envelope, said electron gun assembly producing an electron beam that forms a beam spot at electron beam landing locations on said screen;
- a core made of a magnetic material;
- a plurality of deflection windings magnetically coupled to said core for producing a main deflection field in a main deflection region between a beam entrance end and a beam exit end of said magnetic core that deflects the electron beam to the beam landing locations;
- and
- first and second quadrupole windings of said plurality of deflection windings that form a double quadrupole arrangement in said deflection yoke for producing a quadrupole deflection field in said main deflection region.
2 more elements
Dependencies are inferred from the claim text.